This invention relates generally to pipe couplers, more specifically to an adjustable coupler with an improved gasket.
Clamps and couplers used to connect sections of pipe, end-to-end, are known to the art. Such clamps often are employed to connect sections of pipe or hopper tees on tank cars. In certain applications, particularly in dry bulk hauling, the integrity of the seal at the pipe connections is critical in preventing cross contamination of the products sequentially hauled in the tank cars. Often pellets or powders are hauled in the tank cars. The pellets or powders are unloaded through gravity gates valves or hoppers located on the bottom of the tank cars. Hopper tees attached to the bottom of the hopper are connected to collection pipes. Sometimes a vacuum is employed through the pipe to facilitate the emptying of the dry bulk products. All of the dry bulk product must be removed to prevent contamination of subsequent loads. For example, if the hauler is carrying black plastic resin beads, all of the black plastic resin must be removed from the car, as well as the hopper and piping, to prevent contamination of a subsequent white or other colored plastic resin load. Another example is the transportation of edible white flour. If flour is trapped in the tank car or the piping system and develops mold, a subsequent flour load will be exposed to the mold. Obviously, there can be cross contamination of bulk liquids as well as bulk dry loads. Such contamination can destroy a load, force its disposal, and at heavy costs.
It is known in the art that contamination can occur at the point of coupling the pipes and the hopper tees. Prior art clamps employ gasket seals that can trap product. FIGS. 1-4 illustrate components of a typical prior art clamp. Prior art clamp 1 is a typical overcenter clamp having two semi-circular sides 3 and 5 connected by hinge 7. A conventional overcenter lever 9 and cam 10 clamping means is used to draw the two halves tightly together to surround the clamp joint. A deformable gasket 11 lines the interior groove 12 of clamp 1. A deformable gasket of the prior art type is shown in FIGS. 3 and 4. As can be seen, gasket 11 has outer walls 13 and 14 with a center member 16 designed to deform and press against the pipe joint. Gaps 18 and 20 between the respective sides and the middle member create areas in which material, for example, dry bulk material such as plastic resins or flour, can become entrapped. It is nearly impossible to remove such material once it is lodged deep in the gaps 18 and 20.
There are other problems other than cross contamination associated with prior art clamps such as clamp 1. Such prior art clamps have no means for adjustment. The clamp, even when new, can be difficult to open and close. Lever 9 and cam 10 wear during use until clamp 1 loosens and fails. This type of clamp must be changed and discarded, leading to waste and increased costs.
Furthermore, such clamps of the type shown in FIG. 1 are made of cast iron and mild steel parts. Clamp 1 can corrode from exposure to the environment. Once corroded, the clamp is nearly impossible to remove from the pipe P or hopper T. The user must pry lever 9 with a pry bar or length of small diameter pipe. Then the user must beat two halves 3 and 5 apart with a hammer to separate them.
Finally, such clamps are not versatile in that they are not easily adapted to connect different pipe sections together. For example, the clamp may be needed to connect two sections of smooth pipe, connect two section of grooved pipe or connect a smooth pipe to a grooved pipe. Prior art clamps may work to connecting similar pipes, but do not accommodate different styles of pipe.